a) At this point, the grade is 27.1
b) The lowest possible grade is 81
How to get the grades of the student?
a) At this point the student has 81 in homework and 95 on the first project.
Remember that the homework is worth 10% of the final grade, and each project is worth 20%, then at this point the final grade is:
F = 0.10*81 + 0.20*95 = 27.1
b) The student gets 72 on the second project and 71 on the third project, at this point the final grade is:
F = 27.1 + 0.20*72 + 0.20*71 = 55.7
Now the student wants to get a final grade of 80, then if we define x as the grade on the final exam (which is worth 30%) we must have that:
55.7 + 0.30*x = 80
Now we can solve this for x:
x = (80 - 55.7)/0.30 = 81
The lowest possible grade that he must get is 81.
If you want to learn more about percentages:
https://brainly.com/question/843074
#SPJ1